Abrasive drum for leather surfacing machines and the like



G. M. CURTIN ABRASIVE DRUM FOR LEATHER SURFACING MACHINES AND IHEYLIKE Filed Nov. 21, 19:56 2 sheets-sheet 1 gmc/vwo@ GEURGE M. E'uRT/N April 6, 1937. v G- M, URT|N 2,076,193

A BRASIVE DRUM FOR LEATHER SURFACING MACHINES AND THE LIKE -2 Sheets-Sheet 2 Filed Nov. 2l, 1936 mi; l I

73 TOLD,

l l v v Fl g 5 GED/PGE M. uRT/N F1g4 l My Patented Apr'. t, 1937 UNITED sTATlazs` PATENT o-FFICE] s I 2,016,193; 'Y

BnAs'rvE DRUM Fon LEATHER `SURFACING. MAcnmEsANn'rHnLum` tion of New York Application November 21, 1936, serial No. 112,105

4 claims. (ci. s1-194) The invention relates to abrasive drums. f One object of the invention is to provide an abrasive drum for Lholding sheet abrasive material for a leather surfacing machine which holds 5 the sheet material very tightly. Another object of the invention is to provide a drum ofthe character indicated upon which may be mounted paper or other abrasive sheet material of parallelogram shape. YAnother object of the invention is to provide a drum which will hold the sheet material without wrinkles and which .may be operated at high speed and Vunder great pressure without tearing the abrasive sheet. Another object of the invention is to provide an abra`` sive drum of the character indicated which can be surfaced and resurfaced with abrasive' paper or other abrasive sheetmaterial very quick- Iy and easily. Other objects will be in part obvious or in lpart pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

l and arrangements of parts, as will be exemplified in the structure tobe hereinafter described, and the scope of the application of which will be indi- 25 cated in the following claims.

In the accompanying drawings in which is illus'trated one of many possible embodiments of the 'mechanical features of this invention,

Figure 1 is an axial sectionalview of a drum 30 constructed in accordance with the-invention,

Figure '2 isa view, partly in end elevation and partly in cross section, of the drum,

Figure 3 is a longitudinal elevation of the drum, Figure 4 is a plan view of -the abrasive sheet 35 material showing how it is cut,

Figure 5 is a transverse vertical sectional view of a leather surfacing machine incorporating the drum of the invention.

Referring rst to Figure 1, Iprovide a horil40 zontal shaft l0' constituting the axial shaft for the abrasive drum. I further provide a cylindrical drum II having an outer unbroken cylindrical surface, as indicated, made of castiron or` -other suitable material and, if desired, made up 45 in sections but joined by weldingl or the like to form a practically integral structure. The drum I I has -diametral web portion's'IZ, I2 having hubs I3, I3 which are press tted onto the shaft I0.

Pinned to the journal portions I3, .I3 by means 50 of pins I1 are a pair of holders I3','.\.I8. In one end of the holders I8, I8 are jurnal'ed stud pinion gears having grooves 2l in the stud portion thereof into which grooves project screws 22 locked in place by nuts 23 in order to hold the 55 pinions 20 in position. Each pinion 20 has a square front portion 24 to receive a suitable end wrench which may be inserted through openings 25 in drum heads 26.

The stud pinion gears 20 mesh with large gears formed on externally threaded sleeves 3|. Ex-

ternally threaded sleeves 3l t in internally threaded hub portions 32 of the drum heads 26.

The gear portions 30 are held close to the holders I8 by means ofguiding members 33 which are ysecured to the holders I8 by means of bolts 34.

Projecting inwardly from each head 26 is a plate 35 having a slot 36 in which fits a pin 31 attached f .to and projecting inwardly from the drum I I. When the wrench is inserted in one of the' holes 25 and the stud gear 20 is rotated, the gear 30 is revolved and one direction of rotation forces the corresponding head 26 outwardly.

' However, owing to the pin 31 and slot 36. the

head in question must slightly, revolve during its outward movement. The pitch of the slot 36 is such as to force the drum heads 26 outwardly. in a spiral direction which has the same pitch as the abrasive paper or `otherl abrasive sheet material 40 on the 'drum II.

The-present invention incl des simplified and highly effective clamps for clamping the abrasive I paper 40 to the drum heads 26. Referring now to vFigures '1, 2, and 3, theclamps which are `designated as a whole by the.numeral 4I are preferably three in numbenfor each drum head 26, that is to say there are six clamps in all. Each4 of these clamps 4I may be just like every other one and any clamp will go on either end of the drum.v Each clamp'4l comprises a. 120 arcuate end portion '42 fitting over the ends of annular anges43 of the drum heads 26 together with an outside inwardly extending lip 44 also extending 120 around the. circle and an inside inwardly extending lip 45 likewise extending 120 around the circle. I provide two-bolts 46 for each clamp 4I extending through the lip 45 and abutting the flange 43. I may provide more bolts 46, if desired, but two thereof are found to 'be adequate.

Considering now the mounting of paper or cloth upon the drum II, I cut the sheet material into the parallelogram shape shown in Figure 4. I prefer to use abrasive paper. I then windt the paper on the drum II, as shown in Figure 3, and place the threeclamps 4I inposition and tighten the bolts 46. If the paper is wrinkledin any opening or seam 50 as possible. I do not overlap the paper unless there is a groove in the drum provided for that purpose. With the present improved clamps and drum in a leather surfacing machine of the type illustrated herein and to be described and when surfacing certain leather materials, I may use a cylindrical drum without any groove, but for other conditions of operation I prefer to use a groove and overlap the paper, as disclosed in copending application of Seymour J. Hallsted, Serial No. 21,733.

I now place the wrench in one of the openings 25 and turn the pinion stud 20. In order not to cause the paper to wrinkle I tighten rst one and then the other of the pinion studs 20 and experience will soon show an operator how to tighten the paper Without producing wrinkles as sometimes one and sometimes the other of the pinion studs should be turned the most to tighten the paper without producing any wrinkles therein. When the last pinion stud 24 to be tightened has been turned about as tight as it can be with the strength of an ordinary man, the paper is properly applied and friction holds'the paper taut and prevents slippage.

-Referring now to Figure l5i, I shall briefly de scribe the machine in which the abrasive drum is preferably used and in connection with which it presents the features and advantages hereinbefore indicated. This machine is more fully described in the aforesaid coperiding application of Seymour J.Hallsted and also in my own copending application Serial No. 20,963. Such a machine includes a pair of side frames 5| only one of which isshown in Figure 5. These side frames maybe of inverted U-shape, thus collectively constituting the four legs of the machine. 'I'here is further provided for each side frame member a fore and aft connecting frame member 52 which maybe U-shaped in cross-section.

There is provided at the front and back of the` machine frame members 54 and 55 respectively, connecting the legs of the U-shaped side frames and which frame members 54 and 55 are X- shaped when viewed in front elevation.

The front part of the top of each side frame slide 56 in order to guide the slides forl rectilinear motion. Extending from the inside of the horizontal portion of the frame members 5| are studs 60 upon which are mounted bell crank levers 6| having arms extending vertically and horizontally. In the vertical arm of each bell crank lever 6| is a slot 62 and in these slots are studs 63 fastened to the aprons 51. The horizontal arms of the bell crank levers 6| are connected by means of pins 64 to links 65 extending downwardly to levers 66, the links 65 being connected to the levers by means of pins 61. The levers 66 are freely movable upon a shaft 69 which extends between brackets 10 bolted to the under side ofthe frame members 52. the rear ends of the levers 66 are square pins 1| each adapted to receive oneor a plurality of detachable weights 12. Connecting the front portions of the levers 66 is a wooden plank treadle member 13. Thus in a manner more fully described in the aforesaid application of II-Iallsted,

the slide 56 may be moved to the front of the machine, that is toward the operator whenever he steps upon the plank 13, and the operator may move one side of the slide 56 more than the Projecting laterally from other by stepping upon one side or the other of the plank 13.

Still referring to Figure 5, uprising from the slides 56 are journal members 80 mounting a shaft 8|. Secured to the shaft 8| and between the journals is a rubber covered roller 82. In order that there shall be no binding of the shaft 8| in the journals 88, these journals'are swiveled on the slides 56 by means of vertical trunnions 83 for the journal member; 80 which rest in vertical bores of annular supporting members 84 for the journals 89.

There is provided a drive for the rubber feed roller 82, not illustrated herein but which may be as shown in my aforesaid copending application or may be of the type shown in my U. S. Patent No. 1,975,349. The rubber covered roller 82 is driven in a clockwise direction and at a very much lesser angular velocity than the abrasive drum The abrasive` drum is preferably driven by direct drive connection to a motor, not shown, the shaft I0 being mounted in suitable journal blocks 85.

There is provided a pinch roller preferably of steel which cooperates with the rubber roller 82 to feed the leather goods or othermaterial. The pinch roller 90 is mountedupon a shaft 9| which in turn is mounted in journal portions in the front of long arms 92 that are articulated on pins 93 to the upper forked ends 94 of standards 95 adjustably secured to the side frame members 5|. The standards 95 are securely but adjustably secured to the side frames I0 and are U- shaped; they have front upright portions 96 with horizontal inwardly extending portions 91 receiving'bolts 98 that extend through the arms 92 and also providing a surface to receive the ends of bolts 99. The bolts 99 are threaded into the arms 92 but the bolts 98'are received loosely in holes in the arms 92. Consequently the arms 92 and when the desired position of adjustment is reached the parts can be securely locked by tightening thebolts 98.

The leather to be treated is placed by the operator upon a table |09 extending between supports |0| bolted to the slides 56, and the operator first steps upon the treadle platform 13 to withdraw the rubber roller 82 from the drum whereupon he places the leather under the pinch roller 90 and allows the rubber roller 82 to move toward the drum The machine then feeds the leather toward the abrasive drum the front side of which is moving downwardly. The clamping and tightening means for the abrasive paper cooperates with the features of the machine described and particularly the adjustment features to permit a very fine finish within very close vtolerances to be achieved. 'I'he clamp of the invention holds the abrasive paper with adequate tightness to withstand the very heavy friction involved in finishing giove leather and the the drum interfering with the paper. In other,

a circle. The bolts 46 constitute positive means u1-0 binders, if desired, the abrasive grains may be oriented, as by the electrostatic method of deposition which is now understood in this art.

It will thus be seen that there has been provided by this invention an apparatus in which 15 the various` objects hereinabove set :forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the' em- 20 bodiment aboveset forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claimz- 1. An abrasive drum comprising a metalcylinder, a pair of heads for said abrasive drum,

means to move the heads outwardly in a spiral course, and a plurality of clamps to hold sheet abrasive material to the heads and thereby to hold it on the drum, each clamp being in the form of a segment of a circle and U-shaped in' cross-section and having a plurality of bolts, and anges on the heads to receive the clamps.

2. An abrasive drum comprising a metal cylinder, a pair of heads for said abrasive drum,

means to move said heads outwardly, and a' plurality of clamps to hold sheet abrasive material to the heads, each clamp being in the form of a segment of a circle, and means .to hold the clamps against the peripheries of the heads.

3. In apparatus of the class described a shaft, a drum on said shaft, a. pair of heads to said drum, means to move said heads away from each other, a flange on each head, and a clamp fitting over the end of each flange, and means to draw each clamp toward said shaft.

4. In apparatus of the class described, a segmental clamp U-shaped in-cross section and bolts on the inside of the clamp.

' GEORGE MONROE CURTIN. 

